Increase in the use of stents, leads, and ablation techniques in branch vessels has provided an increased demand on the placement techniques for these devices. For some procedures, it is necessary to initially position a guidewire into a desired part of the lumen of a desired vessel or duct, such as a blood vessel. After the guidewire is positioned within the desired location, a catheter or other tubular device may be positioned over the guidewire and used to convey other medical instruments into the desired blood vessel or duct.
Alternatively, a guiding catheter is used to negotiate the vasculature of a patient. One example of a guiding catheter is described in U.S. Pat. No. 4,898,577 to Badger et al. The Badger guiding catheter includes a single elongate shaft that has a deflectable distal portion controllable by a pull wire. Once the distal portion is at the required deflection or location within the patient, the guidewire or medical instrument is fed through a delivery lumen of the catheter.
The deflectable catheter is controlled at a proximal end of the catheter by a control handle that operates a pull wire to deflect the catheter, for example, as shown in U.S. Pat. No. 6,171,277. In many conventional catheters, the pull wire is disposed within a pull wire lumen, where the pull wire lumen extends from the distal portion of the shaft through an opening at the proximal end surface of the shaft. The pull wire opening at the proximal end surface is directly adjacent to a delivery lumen that extends from the distal end through the proximal end surface, which has several drawbacks. For instance, blood which enters the delivery lumen at the distal end can travel to the proximal end of the shaft and enter the pull wire lumen, potentially resulting in contamination issues. Another potential drawback is when the blood entering the pull wire lumen clots within the pull wire lumen or around the pull wire, the operation of the pull wire is impeded, rendering it difficult to manipulate the distal end of the shaft. Another potential drawback with this pull wire lumen and delivery lumen is the risk of embolism.
Accordingly, what is needed is a deflectable catheter that overcomes the shortcomings of previous deflectable catheters. What is further needed is a deflectable catheter that allows for more accurate positioning of the distal end of the deflectable catheter.